The present invention relates to an encoder adaptable to UVLC (Universal Variable Length Code), and more particularly to an encorder that can achieve the UVLC coding requirements of TML6 in H.26L video compression standard.
VLC (Variable Length Code) coding is a method to eliminate statistical redundancy in compression algorithm, and is generally the last step in video compression algorithm.
Conventional VLC coding will find the best coding value for the actual data according to statistical characteristics thereof so as to achieve the compression effect.
In H.26L, VLC will have a constant probability distribution that is called UVLC (Universal Variable Length Code). Whether a UVLC can really achieve the compression effect or not depends upon whether the input thereof complies with the constant probability distribution. In H.26L, some look-up tables are used before UVLC coding, in order to modify the input to comply with the constant probability distribution.
The coding of UVLC is a brand-new method, and there is no any hardware that implements the UVLC up to the present day.
It is therefore an object of the present invention to provide an UVLC (Universal Variable Length Code) encoder that can comply with the H.26L standard. The encoder is very simplified by modifying the codeword number and utilizing a codeword alignment technique, while a look-up table can absorb the effect of codeword number""s change before the H.26L coding, thus there is no any effect the whole system.